Acidic low-level radioactive waste liquid treatment method and system, and nuclear fuel post-treatment plant system

Abstract

The invention discloses an acidic low-level radioactive waste liquid treatment method. The method comprises the following steps: carrying out multi-stage acid separation treatment on an acidic low-level radioactive waste liquid, and separating out concentrated nitric acid to obtain light waste liquid; and carrying out multi-stage precision treatment on the light waste liquid, and separating nuclides to obtain a purified liquid. The invention further discloses an acidic low-level radioactive waste liquid treatment system.The treatment system comprises an acid treatment device and a fine treatment device, the acid treatment device is used for carrying out multi-stage acid separation treatment on the acidic low-level radioactive waste liquid, concentrated nitric acid is separated out, and light waste liquid is obtained; and the fine treatment device is connected with the acid treatment device and is used for separating nuclides in the light waste liquid to obtain purified liquid. The invention further discloses a nuclear fuel post-treatment plant system. Radionuclide in the acidic low-level radioactive waste liquid can be effectively removed, nitric acid can be effectively separated, the purified liquid with low salt content is obtained, the emission requirement can be met, pollution to the environment is avoided, the use amount of fresh nitric acid suitable for nuclear fuel post-treatment plants can be reduced, and the cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of nuclear engineering, and in particular relates to a treatment method and system for acidic low-level waste liquid, and a post-treatment plant system including the treatment system for low-level acidic waste liquid. Background technique [0002] In the nuclear fuel reprocessing plant, the low-level condensate (low-level radioactive waste liquid) produced after evaporation treatment in the evaporation system has problems such as high acidity, which cannot meet the direct discharge standard and needs further treatment. According to the treatment requirements: the radioactive level of the waste liquid purified by low-level condensate β / γ≤40Bq / L, α≤4Bq / L; the pH value of the waste liquid must be between 6-7, and the amount of concentrated liquid returned to the upstream system It needs to be ≤10%; and, since the low-release condensate usually takes the form of overhead discharge, the salt content in the waste ...

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Problems solved by technology

[0003] At present, conventional low-level waste liquid treatment technologies mainly include methods such as evaporation concentration, adsorption, neutralization, and ion exchange. However, these methods have at least the following disadvantages: the low-level waste liquid from the reprocessing plant has passed through the evaporation system 2-3 times Evaporation, the purification effect obtained by evaporation again is limited, and it is difficult to meet the discharge requirements; the adsorption technology can only remove specific nuclides in the waste liquid, and cannot change the pH of the waste liquid; the waste liquid after further treatment by the neutralization method contains The amount of salt can reach 10g / L, which cannot meet the requirements of overhead discharge; ion exchange technology is currently used in pilot plants to treat low-level condensate, but due to the high concentration of hydrogen ions in low-level waste liquid, its There is a competitive relationship with nuclide ions, which will inhibit the dissociation of exchangeable ions on the cationic resin, resulting in a sharp drop in the exchange capacity of the cationic resin, causing the ion exchange bed to penetrate quickly, resulting in a large amount of radioactive waste resin, which will increase the subsequent waste Difficulty of handling

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